This invention relates to an actuator. Specifically, the present invention relates to a sealing joint and casing for a stopcock actuator.
A stopcock actuator comprising a system for distributing drive fluid to the actuating cylinder of a seal is already known. The distribution system and the actuating cylinder are housed in separate envelopes which have to be connected by means of tubes or conduits.
This arrangement is bulky and makes assembly complicated.
The invention overcomes these drawbacks with a sealing joint and a stopcock actuator casing, in which the base of the casing is shaped so as to provide the connections for the distribution of fluid to the cylinder.
The base of the casing is, in particular, formed with a through-hole for a device for monitoring the position of the seal and the underside of the base is subdivided into at least three compartments, the first of which surrounds the hole whilst the second and third are each formed with two orifices passing through the base. The base may also be subdivided into at least five compartments each of which, with the exception of the first, has two orifices passing through the base, one of the orifices in the fourth compartment communicating on the upper surface of the base with one of the orifices in the second compartment, and one of the orifices in the fifth compartment communicating on the upper surface of the base with one of the orifices in the third compartment. These orifices provide a means of communication between the distribution system for the drive fluid and the cylinder, with the possibility of inserting a flow regulating device, e.g. in the form of a screw-type needle valve, in the orifice in the fourth compartment and the one in the fifth compartment communicating with one of the orifices in the second compartment and the third compartment.
Preferably, a sixth compartment is provided with a through-orifice and an orifice opening into a conduit provided in the base and opening outside the casing. This allows the drive fluid to escape from the actuating cylinder and also enables any fluid which has leaked into the inside of the casing to escape from there.
The invention also relates to a one-piece elastomer sealing joint shaped so as to define a mesh, at least in part, characterised in that it comprises, projecting into the mesh, a solid part attached to a first side of the mesh by means which enable the solid part to stand out from the plane of the mesh. Preferably, a flexible bar is provided linking the solid part to the first side of the mesh and another flexible bar is provided linking the solid part to the two sides of the mesh adjacent to the first side, the two bars being notably perpendicular. The solid part is able to move up out of the plane of the mesh under the effect of pressure or be returned thereto. Preferably, the solid part does not extend as far as the side opposite the first side. In any case, it is not attached thereto. Advantageously, it takes up one-third to two-thirds of the surface of the mesh. The joint may be in the form of a net and may define a plurality of meshes, at least two of which have a solid part. This sealing joint makes it possible to seal the pneumatic connections between the body of the cylinder and the casing of the actuator in a way which is very simple to produce and assemble.